This proposal is to continue the long term work of my laboratory on the development of synthetic methods, more particularly those that would be suitable for the control of regio- and stereochemistry and to apply them in the total synthesis of biologically interesting molecules. The specific molecules which are targets of our efforts, in the context of this application, are gelsemine, the curare alkaloids, calcitriol, the tetracycline antibiotics and the antitumor taxol. Some problems are related to methodology toward a structural type rather than toward a specific target: we are studying intramolecular Diels Alder additions involving benzofuran rings as dienophiles as a route to the morphine alkaloids framework.